Thread rolling head

ABSTRACT

A thread rolling head comprises a bearing unit, in which at least two profile rollers, preferably at least three profile rollers, are rotatably mounted, and a shank section coupled to the bearing unit. Adjacent profile rollers delimit an insertion section into which a workpiece to be machined can be inserted. The bearing unit is built from at least two modules each forming a functional unit, wherein the modules each have a fastener through which modules can be connected together and can be exchanged for other modules also each forming a functional unit. One of the modules has fasteners for connecting to corresponding fasteners of the shank section.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to EP 13 197 742.3, filed Dec. 17,2013, the content of which is incorporated herein in its entirety byreference.

FIELD OF THE DISCLOSURE

The disclosure relates in general to a thread rolling head.

BACKGROUND

Thread rolling heads can be, for example, axial thread rolling heads orradial thread rolling heads. They can have, for example, three profilerollers uniformly distributed about an insertion section. A workpiece,cylindrical for example, can be inserted in the longitudinal directioninto the insertion section. With axial thread rolling heads, machining(that is, forming the threads) on the workpiece occurs in the course ofinsertion into the insertion section. With radial thread rolling heads,the profile rollers for machining are positioned radially onto theworkpiece after the insertion of the workpiece. Generally, there isadditionally an opening mechanism with which the profile rollers can bedisplaced between a machining position and an open position, in whichthey are displaced radially outward. After the machining process, therollers are moved into the open position, and the thread rolling headcan be removed from the workpiece without collision. Furthermore, thecross-section of the insertion section may be adapted by adjusting thespacing of the profile rollers to each other. In this manner, the threadrolling head can be adapted to different workpieces to be machined andbe precisely adjusted.

Thread rolling heads are complex systems composed of a plurality ofindividual parts. This complexity is due to the requirements of thethread rolling heads, among others small construction size andsimultaneous coverage of a large machining range. A thread rolling headis known, for example, from German document DE 44 30 184 C2. Here, on ashank that can be fixed in a machine tool, a coupling section extendsthrough a spring housing composed of a plurality of components into agearing mechanism arranged at an intermediate plate of the threadrolling head. A front plate is fastened to the intermediate plate usingscrew connections. Three profile rollers, each on an eccentric shaft,are held mounted rotatably between the front plate and the intermediateplate. The fastening occurs via distance bolts, arranged between thefront plate and the intermediate plate, into which threaded pins arescrewed from the one side through the front plate, and which comprise anexternal thread on the other end thereof that extends through theintermediate plate and the spring housing up to the shank. Lock nuts arescrewed onto the external thread of the distance bolts.

A further thread rolling head is known from European document EP 1 555072 B1. With this thread rolling head, a fixing section of the shank forfixing into a metal-cutting machine on the one side and a couplingsection of the shank for coupling to the bearing unit of the threadrolling head on the other side are separated parts that are connectedtogether axially and releasably fixed against rotation via connectingsections. In this manner it is possible to provide another fixingsection of the shank, wherein the coupling section of the shank remainsconnected to the bearing unit of the thread rolling head. In the samemanner, a plurality of different thread rolling heads can be used in afixing machine.

BRIEF SUMMARY

During operation, thread rolling heads and thus also the individualthread rolling components experience wear. Worn out parts must bereplaced. Due to the complex assembly and disassembly of known threadrolling heads, replacing parts is complex and requires extensiveknowledge of the thread rolling head. This can represent a problemespecially for a customer using the thread rolling head. Thread rollingheads, such as those described in the document DE 44 30 184 C2, must benearly completely disassembled for maintenance or exchange of parts andthen reassembled to be functioning properly. Typical components thatexperience wear are fastening or blocking plates, profile rollers oreven eccentric shafts. Maintenance and exchange of parts in this mannerare unfavorable from an economic point of view. Because this is alsoassociated with a lengthy expenditure of time, this results in acorrespondingly long machine downtime. The personnel performing theexchange must further be trained regularly in detail.

An exchange of components of a thread rolling head can also occur forother reasons. Thus, great demands for flexibility are placed on threadrolling heads during operation. Along with the rolling of metricstandard threads, for example, custom threads with special pitch angles,teeth and a plurality of further profiles may also be rolled. In eachcase, at least the profile rollers must be exchanged, and frequently theeccentric shafts and distance bolts must also be exchanged. This alsoleads to the problems explained above.

It is thus desirable to provide a thread rolling head that can be usedeconomically even in the case of wear or changed machining requirements.

A thread rolling head described herein has a bearing unit in which atleast two profile rollers, and preferably at least three profilerollers, are rotatably mounted. It also has a shank section coupled tothe bearing unit, wherein adjacent ones of the profile rollers delimitan insertion section into which a workpiece to be machined can beinserted. A bearing unit is built from at least two modules each forminga functional unit, wherein the modules each have fastening means, bywhich they can be connected together and can be exchanged for othermodules also each forming a functional unit. One of the modules hasfastening means for connecting to corresponding fastening means of ashank section.

The profile rollers between each other delimit an insertion section intowhich a workpiece to be machined can be inserted, in particular in thelongitudinal direction. Thus, it can be an axial thread rolling head ora radial thread rolling head. It has at least two profile rollers,preferably three or more profile rollers. The profile rollerstherebetween delimit an insertion section that is, for example,cylindrical or tapering cone-shaped in the direction of insertion of aworkpiece. A shank section is conventionally coupled to the bearingunit. The thread rolling head can be fixed in a metal-cutting machineusing the shank section. The shank section can be movable in the axialdirection with respect to the bearing unit. The longitudinal axis of theinsertion section can run, in particular, coaxial to the longitudinalaxis of the shank section.

For inserting a workpiece, for example a cylindrical workpiece, into theinsertion section in the axial direction, an axial relative movement isrequired between the workpiece and the thread rolling head. For thispurpose, the workpiece or the thread rolling head, or both, can be movedin the axial direction. With an axial thread rolling head the machining,thus forming the thread, occurs in the course of inserting the workpieceinto the insertion section. Thus, in this case, the cross-section of theinsertion section in the machining position of the profile rollers issmaller, at least in sections, than the cross-section of the workpiece.With a radial thread rolling head, after the axial insertion of theworkpiece into the insertion section, there is a radial positioningmovement of the profile rollers onto the workpiece, and thereby themachining occurs. For the machining, the workpiece can be rotated,wherein the thread rolling head is arranged fixed against rotation.However, it is also possible that the workpiece is arranged fixedagainst rotation and the thread rolling head is rotated in the course ofthe machining.

The shank section can be axially movable with respect to the bearingunit, as explained. Then, the shank section in a first axial relativeposition can interact, using fastening means thereof, with correspondingfastening means of the bearing unit, whereby both parts are coupledtogether fixed against rotation. A gearing mechanism and a spring may belocated between the shank section and eccentric shafts bearing theprofile rollers in such a manner that in a second axial relativeposition of the shank section with respect to the bearing unit, in whichthe fastening means are disengaged, the spring is tensioned with arotation of the bearing unit in a first direction of rotation withrespect to the shank section or, respectively, the tensioned springrotates the bearing unit relative to the shank section in the opposite,second direction of rotation. Also, a spring can tension the shanksection and the bearing unit with respect to each other into the firstrelative position.

Mechanical switching means, for example, can contact the workpiece so asto bring the shank section and the bearing unit into the second relativeposition. In this manner, an opening and closing of the thread rollinghead is possible by moving the profile rollers between the machiningposition thereof and a radially opened open position. In the openposition, the cross-section of the insertion section is greater than thecross-section of the workpiece, such that the thread rolling head aftermachining can be removed from the workpiece without collision therewith.The profile rollers, in particular in the machining position thereof,may be uniformly distributed and arranged concentric to the insertionsection. For example, three profile rollers may be so arranged.Naturally the longitudinal axes of the profile rollers can be slightlyangled with respect to the longitudinal axis of the insertion section.The shank section along with the fastening means for connecting to thebearing unit can have further fastening means with which it can be fixedin a metal-cutting machine.

The bearing unit, which can be coupled to the shank section, is builtfrom a plurality of modules which each form a functional unit accordingto an implementation of the invention. The modules are each composed ofa plurality of components and preassembled into a unit, or respectivelya module. They can be connected modularly together, or respectively tothe shank section, and can be released again from each other, orrespectively from the shank section, and thus can be exchanged for othersuch modules. For connecting the modules together, or respectively tothe shank section, in a functionally secure manner, the modules eachhave suitable fastening means. During operation of the thread rollinghead, torque can be transferred at least via several, in particular viaall of the fastening means. The fastening means can provide, forexample, a form-locking connection between the modules, or respectivelyto the shank section. The shank section can also be constructedmodularly.

Due to the modular construction of the thread rolling head according tothe teachings herein, the thread rolling head can be easily andeconomically repaired and maintained, as well as adapted to differentoperational requirements. For this purpose, it is desirable that onlythe fastening means serving as separation points between the modules, orrespectively to the shank section, are loosened. Then, one or moremodules each forming a functional unit can be exchanged for one or moreother similar modules also forming a functional unit, in that theappropriate fastening means can be connected together again. Here,optionally-provided modules can also be inserted in a flexible manner inthe thread rolling head, or can be removed therefrom. Here, in contrastto the documents explained above, it is not necessary to disassemble theentire thread rolling head, or the bearing unit thereof, into respectiveindividual parts. The modules are exchanged easily and quickly.Undesired prolonged machine down times are avoided. Additionally, thecustomer using the thread rolling head can perform the exchange withoutproblems, and without extensive knowledge of the assembly of theindividual components. For this purpose, the fastening means aredesigned such that they each permit a functionally secure assemblyallowing the function of the thread rolling head. For facilitating theassembly of the modules, fastening markings that display the correctassembly position can be provided on several or all modules.

The fastening means of at least two of the modules can provide a uniquefastening position of these modules to each other. In someimplementations, it is also possible that the fastening means of atleast two of the modules provide exactly two fastening positions ofthese modules to each other. By allowing two fastening positions, a usercan assemble the modules, depending on the respective fixing situation,to a metal-cutting machine. The assembly can be made such that a scaledisplaying a profile roller spacing, for example, is easily visible.

According to a further design, a first module of the bearing unit is aprofile roller cage holding the profile rollers using fastening means.Optionally, a second module of the bearing unit is a spring housing witha spring arranged in the spring housing and with first and secondfastening means, wherein the spring housing with the first fasteningmeans thereof can be connected to fastening means of the shank section,and wherein the spring housing with the second fastening means thereofcan be connected to the fastening means of the profile roller cage.

Modules provided with these designs each fulfill one function as afunctional unit. The profile roller cage bears the profile rollers in asuitable manner. The spring housing supports a spring, for example aspiral spring, which can be pretensioned in the machining position ofthe profile rollers so that the spring, after releasing suitablemechanical or other switching means in the course of the tension releasethereof, moves the profile rollers from the machining position into theopen position. The displacement of the profile rollers between themachining position and the open position occurs, for example, by arotation of the spring housing, and thus the bearing unit, relative tothe shank section, caused by the spring. For movement of the profilerollers from the open position into the machining position, the bearingunit, for example, can be rotated with respect to the shank section inan appropriate manner such as manually against the pre-tensioning of thespring of the spring housing.

According to a further design, the shank section may also be constructedfrom at least two modules, wherein a first module is a closing unithaving first and second fastening means, and wherein a second module isa shank having fastening means. The first fastening means of the closingunit can be connected to the fastening means of the shank, and thesecond fastening means of the closing unit provides fastening means withwhich the spring housing can be connected to the first fastening means.At least the closing unit likewise forms a functional unit built from aplurality of components. It is further possible that the fastening meansof the shank and the second fastening means of the closing unit areidentical in design. Then, the spring housing with the connected firstfastening means can be selectively fastened to the closing unit, or if aclosing unit is not required or desired, can be fastened directly to theshank.

The closing unit that can be connected to the spring housing serves toconnect the bearing unit to the shank that can be fixed in a machinetool. Here it is possible that the shank section, formed from theclosing unit and shank securely fastened thereto, is movable in theaxial direction with respect to the bearing unit, thus in particular,also with respect to the spring housing and profile roller cage. Forexample, in a first axial relative position between the shank sectionand the bearing unit, rotation of the spring housing relative to theshank section due to the pretensioned spiral spring it can be preventedusing a suitable dog clutch. In contrast, in a second relative axialposition between the shank section and the bearing unit, which positionresults from releasing mechanical switching means, rotation of the shanksection with respect to the bearing unit can be permitted, caused inparticular by the pretensioning of the spring of the spring housing. Thedog clutch can be released for this purpose. In such a design, the firstand second fastening means of the spring housing may be axially movabletogether relative to the remaining components of the spring housing. Thefirst fastening means of the spring housing, in the mounted position ofthe thread rolling head, can be securely connected to the assignedfastening means of the shank section such that, with an axial relativemovement of the bearing unit with respect to the shank section, thefirst and second fastening means of the spring housing do not move withthe bearing housing.

The thread rolling head may have a plurality of different profile rollercages and/or different spring housings and/or different closing unitsand/or different shanks, each designed as a module according to theteachings herein, which can be exchanged with each other in a suitablemanner.

The profile roller cage can have a front plate and an intermediateplate, wherein the profile rollers, together with eccentric shaftsbearing them rotatably, are held between the front plate and theintermediate plate. The profile roller cage can further have a pluralityof distance bolts fastened to the front plate and extending between thefront plate and the intermediate plate. The distance bolts, on the sidefacing away from the front plate, can each extend with an end sectionhaving external threads through the intermediate plate and the springhousing. Lock nuts can then be screwed onto the end sections from theside of the spring housing facing away from the profile roller cage. Thedistance bolts, on the opposite side thereof, can each be connected tothe front plate using a screw connection. The distance bolts then form apart of the fastening means of the profile roller cage, and the locknuts screwed onto the end sections of the distance bolts then form partof the second fastening means of the spring housing. Here, the distancebolts can extend through suitable arc-shaped elongated holes of thespring housing such that rotation is possible between the spring housingand the profile roller cage. During operation, this rotational movementcan be prevented by suitable fastening means, for example, lock nutsscrewed onto the distance bolts.

According to a further design, the fastening means of the profile rollercage may comprise a central ring gear, having external teeth, arrangedon the intermediate plate on the side facing away from the front plate.The profile roller cage further includes a plurality of outer gears alsoon the intermediate plate on the side facing away from the front plate,meshing with the external teeth of the central ring gear, and the outergears are each connected to one of the eccentric shafts, fixed againstrotation. The outer gears can each be connected to one of the eccentricshafts, for example, in a form-locking or press fit manner. The centergear, as with the outer gears, can be mounted rotatably on theintermediate plate. A rotation of the center gear, caused for example bya rotation of the spring housing, then leads to a rotation of the outergears and thus the eccentric shafts, and vice versa. Thereby, in turn,the spacing of the profile rollers to each other, and thus thecross-section of the insertion section, is displaced.

The second fastening means of the spring housing can further comprise acoupling section engaging in a form-locking manner in the ring gear ofthe profile roller cage. The coupling section of the spring housing canbe designed as a toothed splined shaft, wherein the ring gear at theinner surface thereof can have a plurality of engagement grooves runningin the axial direction of the thread rolling head, into which thesplined shaft engages. Furthermore, the distribution of the splinedshaft and the distribution of the engagement grooves formed on the innersurface of the ring gear may be non-uniform, such that the couplingsection can engage precisely in one rotational position into the ringgear.

The first fastening means of the spring housing can have a couplingsection, in particular a form-specific coupling section, and the secondfastening means of the closing unit can comprise a likewise couplingsection in form-locking engagement with the coupling section of thespring housing. It is also possible that the first fastening means ofthe closing unit has a coupling section, in particular a form-specificcoupling section, and that the fastening means of the shank also has alikewise coupling section in form-locking engagement with the couplingsection of the spring housing. With these designs, a form-locking, andthus fixed against rotation, fastening of the modules is possible in aparticularly simple manner through which significant torques can also betransferred.

For precise adjustment of the spacing of the profile rollers in themachining position, the profile roller cage and the spring housing canbe rotatable relative to each other by pre-tensioning, or respectivelyrelaxing, the spring mounted in the spring housing and by changing thespacing of the profile rollers. The spring may be a spiral spring, andthe change in spacing can be caused, in particular, by the gearingmechanism composed of center gear and outer gears described above.

According to a further design, the spring housing may have an annulargroove running in a peripheral direction over the outer surface, inwhich an actuating clip is fastened with a catch so that rotation of thespring housing relative to the profile roller cage is possible via theactuating clip. The actuating clip can be placed in the annular grooveand be securely fixed by screwing in a manner well known for clips.Then, using the actuating clip, the spring housing can be rotatedrelative to the profile roller cage. The catch in particular forms astop for this purpose. According to a particularly practical design, theactuating clip can have an actuating section to which the catch isreleasably fastened, for example by a standard screw connection. Thecatch can then be easily exchanged for another catch, or othercomponents. By providing an actuating clip, the catch can be arranged ina flexible manner in any desired position of rotation on the springhousing. The thread rolling head can be manually closed again using thecatch after the machining process.

These and other embodiments of the invention are explained in thefollowing in more detail using the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawingswherein like reference numerals refer to like parts throughout theseveral views unless otherwise noted, and wherein:

FIG. 1 is a perspective, exploded view of a thread rolling headaccording to a first embodiment of the invention;

FIG. 2 is a first perspective view of a profile roller cage of thethread rolling head of FIG. 1;

FIG. 3 is a second perspective view of the profile roller cage of FIG.2;

FIG. 4 is a first perspective view of a profile roller cage for a threadrolling head of FIG. 1 according to a second embodiment of theinvention;

FIG. 5 is a second perspective view of the profile roller cage of FIG.4;

FIG. 6 is a first perspective view of a profile roller cage for thethread rolling head of FIG. 1 according to a third embodiment of theinvention;

FIG. 7 is a second perspective view of the profile roller cage of FIG.6;

FIG. 8 is a first perspective view of a profile roller cage for thethread rolling head of FIG. 1 according to a fourth embodiment of theinvention;

FIG. 9 is a second perspective view of the profile roller cage of FIG.8;

FIG. 10 is a first perspective view of a spring housing of the threadrolling head of FIG. 1;

FIG. 11 is a second perspective view of the spring housing of FIG. 10;

FIG. 12 is a first perspective view of an actuating clip of the threadrolling head of FIG. 1;

FIG. 13 is a perspective view of the actuating clip of FIG. 12 in asecond operating state;

FIG. 14 is a first perspective view of a closing unit of the threadrolling head of FIG. 1;

FIG. 15 is a second perspective view of the closing unit of FIG. 14;

FIG. 16 is a first perspective view of the closing unit for the threadrolling head of FIG. 1 according to a second embodiment;

FIG. 17 is a second perspective view of the closing unit of FIG. 16;

FIG. 18 is a perspective view of a shank of the thread rolling head ofFIG. 1;

FIG. 19 is a perspective view of the shank for the thread rolling headof FIG. 1 according to a second embodiment; and

FIG. 20 is a perspective view of the shank for the thread rolling headof FIG. 1 according to a third embodiment.

DETAILED DESCRIPTION

A thread rolling head according to an embodiment of the invention shownin FIG. 1 has a shank 10 that has fastening means (not shown in detail)for fixing in a metal-cutting machine, for example. The shank 10 on oneend has fastening means in the form of a coupling section 12. By meansof this coupling section 12, the shank 10 can be connected releasably ina form-locking manner to a corresponding coupling section (not shown inFIG. 1) of a closing unit 16. The coupling sections, for example, can beadditionally screwed together for the secure connection of shank 10 andclosing unit 16. The shank 10 forms a first module and the closing unit16 forms a second module of a modularly-designed shank section. Theclosing unit 16, on the side facing away from the shank 10, comprisessecond fastening means designed as a coupling section 18.

The thread rolling head further has a bearing unit 14, which is designedhere comprising a plurality of modules each forming a functional unit. Afirst module of the bearing unit 14 is formed by a profile roller cage36. A second module is formed by a spring housing 20 in which a spiralspring 22 is held, the outer end of which interacts with a slit withinthe spring housing 20. The spring housing 20 has first fastening means(not seen in FIG. 1) formed as a coupling section that can be connectedin a form-locking manner to the coupling section 18 of the closing unit16 so as to connect the spring housing 20 to the closing unit 16.

The spring housing 20, on the side facing away from the first fasteningmeans, has second fastening means in the form of a coupling sectionformed as a toothed splined shaft 24. The spring housing 20 further hasa ring-shaped annular groove 26, running over the periphery thereof,into which an actuating clip 28 can be inserted. The actuating clip 28can be tensioned in the inserted state in the annular groove 26 using ascrew connection 30, and thus be fastened to the spring housing 20. Acatch 32, serving as a stop, is fastened to an actuating section of theactuating clip 28. Desirably, the fastening is releasable such asthrough the use of, for example, a standard screw connection. It can befurther seen in FIG. 1 that the spring housing 20 on its inside facesaway from the closing unit 16 and in the example shown has threearc-shaped elongated holes 34.

The profile roller cage 36 has an intermediate plate 38 and a frontplate 40. In the example shown, between the intermediate plate 38 andthe front plate 40, three eccentric shafts 42 are arranged, each ofwhich rotatably mounts a profile roller (not shown in FIG. 1). The frontplate 40 and the intermediate plate 38 are held apart, in the exampleshown, using three distance bolts 44. The distance bolts 44 are eachscrewed to the front plate 40 using a screw connection 46. Each distancebolt 44 has an end section 48 with external thread on the end facingaway from the front plate 40. The end sections 48 extend through theintermediate plate 38 and the spring housing 20 and are each guidedthrough an elongated hole 34 of the spring housing 20. The intermediateplate 38 has fastening means (not shown in FIG. 1) on the side facingaway from the front plate 40 into which the splined shaft 24 of thespring housing 20 engages in a form-locking manner. In the assembledstate, the profile rollers of the profile roller cage 36 between eachother delimit an insertion section 50, into which a workpiece to bemachined can be inserted in the longitudinal direction.

FIGS. 2 and 3 show the profile roller cage 36 of the thread rolling headof FIG. 1 in more detail. In particular, the fastening means of theprofile roller cage 36 for fastening to the spring housing 20 can beseen. The fastening means comprise, along with the distance bolts 44 andthe end sections 48 thereof, a ring gear 52 having a plurality ofengagement grooves 54 running along the axial direction on its innersurface. The splined shaft 24 of the spring housing 20, in the assembledstate, engages in the engagement grooves 54 of the ring gear 52. It canbe further seen in FIG. 3 that three outer gears 56 mesh with the ringgear 52 in the illustrated example. The outer gears 56 are eachconnected in a form-locking manner to one of the eccentric shafts 42. Arelative rotation, for example between the spring housing 20 and theprofile roller cage 36, leads to a rotation of the outer gears 56 andthus the eccentric shafts 42 bearing the profile rollers, by means ofthe form-locking engagement of the splined shaft 24 in the engagementgrooves 54 of the ring gear 52. This in turn leads to a change of thespacing of the profile rollers to each other, and thus a change of thecross-section of the insertion section 50. For this purpose, the ringgear 52 is mounted rotatably on the intermediate plate 38 of the profileroller cage 36.

If the splined shaft 24 of the spring housing 20 and the ring gear 52 ofthe profile roller cage 36 are engaged, the profile rollers have apredefined spacing to each other, namely in a machining position. Thespiral spring 22 is tensioned in this machining position. If a thread isformed in a workpiece that is inserted into the insertion section 50formed between the profile rollers, the workpiece moves rotatingly intothe thread rolling head, or respectively the bearing unit 14, until thefeed motion is terminated by a stop (not shown), and the bearing unit 14itself is further moved due to the described feed motion. The bearingunit 14 composed of the profile roller cage 36 and the spring housing 20moves axially relative to the shank section composed of the shank 10 andthe closing unit 16.

The splined shaft 24 and the coupling section 60 formed on the oppositeside of the spring housing 20 (see FIG. 11), which together form thefirst fastening means of the spring housing 20, are formed here on acommon part, which is movable axially relative to the remainingcomponents of the spring housing 20. The coupling section 60 is securelyscrewed to the coupling section 18 of the closing unit 16 such that thepart composed of splined shaft 24 and coupling section 60 do not movewith the bearing unit. The splined shaft 24 however remains engaged withthe ring gear 52 of the spring housing 20 (see FIG. 3). In the course ofthis axial relative movement, claws of a dog clutch (not shown inFIG. 1) become disengaged, and due to the spring effect of the spiralspring 22 there is a relative rotation between the bearing unit 14 andthe shank section 10, 16, wherein this rotation can occur only over apredefined angle of rotation due to the formation of the dog clutch.This relative rotation causes a rotation of the eccentric shafts 42 suchthat the profile rollers move into the open position and the threadrolling head is opened. Here, the splined shaft 24 and thus the ringgear 52 do not rotate. However, because the end sections 48 of thedistance bolts 44 are securely screwed to the spring housing using screwnuts 62 (see FIG. 11), the outer gears 56 meshing with the ring wheel 52rotate such that there is a displacement of the profile rollers. Theworkpiece can now be removed from the thread rolling head.

If the thread rolling head is to be closed again, the bearing unit 14 ofthe spring housing 20, together with the closing clip 28 and the profileroller cage 36, must be rotated in the opposite direction until the dogclutch re-engages. Because the bearing unit 14 with the describedopening movement was removed axially from the closing unit 16 with theshank 10, a tensile force was also exerted on the spiral spring 22. Thedog clutch is reengaged using the thusly generated pre-tensioning. Thus,the profile rollers are again located in the machining position thereof,and the thread rolling head is closed for a new machining process.

FIGS. 4 and 5 show a second exemplary embodiment of a profile rollingcage 36′. This corresponds largely with the profile roller cage 36 shownin FIGS. 2 and 3. It can be inserted into the thread rolling head ofFIG. 1 instead of the profile roller cage 36 shown in FIGS. 2 and 3. Incontrast to the profile roller cage 36 shown in FIGS. 2 and 3, with theprofile roller cage 36′ of FIGS. 4 and 5, the distance bolts 44′ aredesigned such that the profile roller cage 36′ is partially closed overthe periphery thereof. This is desirable for some applications.

Likewise, it is also possible to insert the profile roller head 36″shown in FIGS. 6 and 7 into the thread rolling head of FIG. 1, insteadof the profile roller cage 36 shown in FIGS. 2 and 3. This profileroller cage 36″ again corresponds largely to the profile roller cage 36shown in FIGS. 2 and 3. However, in contrast to the embodiment of FIGS.6 and 7, the distance bolts 44″ and thus also the eccentric shafts 42″are designed longer such that longer threads can be formed due to anenlarged section between the front plate 40 and the intermediate plate38.

It is also possible, for example, to replace the profile roller cage 36shown in FIGS. 2 and 3 by a profile roller cage having a changed angulararrangement of the eccentric shafts 42, in order to form a custom anglefor example.

FIGS. 8 and 9 show a further example of an embodiment of a profileroller cage 36′″ that can be used as a module with the thread rollinghead of FIG. 1. Again, the profile roller cage 36′″ corresponds largelyto the profile roller cage 36 shown in FIGS. 2 and 3. In contrast, inthis exemplary embodiment, the distance bolts 44′″ together with thewall section 58 are constructed such that a closed profile roller cage36′″ is formed.

FIGS. 10 and 11 show the spring housing 20 of the thread rolling head ofFIG. 1 in more detail. The view in FIG. 11 shows the first fasteningmeans of the spring housing 20 formed as a coupling section 60 that isassembled by screwing the spring housing 20 in the coupling section 18of the closing unit 16. FIG. 11 further shows three screw nuts 62 thatare screwed onto the end sections 48 of the distance bolts 44 forfastening the profile roller cage 36 to the spring housing 20. They forma part of the second fastening means of the spring housing 20.

FIGS. 10 and 11 further show a precise adjustment possibility foradapting the spacing of the profile rollers to each other in themachining position. The precise adjustment comprises a slide block 66with a thread, guided on a threaded pin 64. The threaded pin 64 issecurely mounted axially and rotatably in the spring housing 20.Rotation of the threaded pin 64 leads to axial movement of the slideblock 66. The slide block 66 has an elongated hole 68 running in aradial direction into which, in the example shown, one of the endsections 48 of the distance bolts 44 is guided for radial movement.Forward or backward axial movement of the slide block 66 leads thereforeto a relative rotation between the spring housing 20 and the profileroller cage 36, and thus to rotation of the eccentric shafts via theabove-described mechanisms of the ring gear 52 and the outer gears 56,and thus to an adjustment of the spacing of the profile rollers to eachother. A scale 70 is shown on the outside of the spring housing 20 thatdisplays the precise adjustment of the spacing of the profile rollers toeach other. It is understood in this design that the screw nuts 62 mustbe loosened first for the precise adjustment.

FIGS. 12 and 13 are enlarged views of the actuating clip 28. In FIG. 13,the catch 32 is not shown for reasons of clarity. The catch 32 or othercatches or components can be screwed into a screw thread shown withreference number 72.

FIGS. 14 and 15 are enlarged views of the closing unit 16 of the threadrolling head of FIG. 1. Along with the coupling section 18 forconnecting to the spring housing 20, FIG. 15 also shows the couplingsection 74, which engages in a form-locking manner in the correspondingcoupling section 12 of the shank 10. In this example, the engagement isa screw engagement. A closing lever guided in an arc shaped elongatedhole can be seen at reference number 76. FIGS. 16 and 17 illustrate afurther embodiment of a closing unit 16′, which in this case is drivenelectronically and thus has no closing lever. However, the remainder ofthe closing unit 16′ corresponds to that shown in FIGS. 14 and 15. Asseen in FIGS. 14 to 17, the coupling sections 18, 74 each allow anassembly of the closing units 16, 16′ to the spring housing 20, orrespectively the shank 10, in exactly two positions of rotation. Thisdesign allows the user, depending on the concrete installation position,to arrange the components of the thread rolling head such that a scale,for example for the precise adjustment of the spacing of the profilerollers, can easily be viewed. It can be further seen that the couplingsections 12 and 18 of the shank 10 and the closing unit 16, 16′ areidentical in design.

FIG. 18 is an enlarged view of the shank 10 of the thread rolling headof FIG. 1. FIG. 19 is another example of the shank 10′ that can be usedwith the thread rolling head of FIG. 1. The shank 10′ may be a so-calledVDI shank according to DIN 69880 for fixing in a metal-cutting machine.In contrast to the round shank 10 from FIG. 18, the shank 10′ from FIG.19 is not rotationally symmetric. Again, the shank 10′ has fasteningmeans, only partially visible, in the form of a coupling section 12 forconnecting to the closing unit 16. FIG. 20 shows a further example of ashank 10″ that can be used with the thread rolling head of FIG. 1. Thisshank 10″ in FIG. 20 also has a fastening means, only partially visible,in the form of a coupling section 12 for connecting to the closing unit16. The shank 10″ shown in FIG. 20 is a so-called hollow shank taper(HSK) according to DIN 69893 for accommodation in tool machines. Thisshank 10″ is also not rotationally symmetric. The catch 32, serving as astop, can be variably positioned on the periphery of the thread rollinghead due to the actuating clip 28, especially with the use ofnon-rotationally symmetric shanks.

What is claimed is:
 1. A thread rolling head, comprising: a bearing unitin which at least two profile rollers are rotatably mounted; and a shanksection coupled to the bearing unit; wherein: adjacent ones of the atleast two profile rollers delimit an insertion section into which aworkpiece to be machined can be inserted; the bearing unit is built fromat least two modules, each module forming a functional unit and having amodule fastening device through which they can be connected together;each module can be exchanged for other modules also each forming afunctional unit; and one of the at least two modules includes a fastenerfor connecting to a corresponding fastener of the shank section.
 2. Thethread rolling head according to claim 1, wherein the module fasteningdevices of adjacent modules of the at least two modules define a uniquefastening position of the adjacent modules to each other.
 3. The threadrolling head according to claim 1, wherein the module fastening devicesof adjacent modules of the at least two modules define exactly twofastening positions of the adjacent modules to each other.
 4. The threadrolling head according to claim 1, wherein: a first module of thebearing unit is a profile roller cage holding the at least two profilerollers; a second module of the bearing unit is a spring housing havinga spring arranged in the spring housing, the fastener being a firstconnector of the spring housing connecting the spring housing to theshank section and the module fastening device of the second module beinga second connector of the spring housing connecting the spring housingto the module fastening device of the profile roller cage.
 5. The threadrolling head according to claim 4, wherein: the shank section is builtfrom at least two modules; a first module of the shank section is aclosing unit having a first closing unit fastening device and a secondclosing unit fastening device; a second module is a shank having a shankfastening device; the first closing unit fastening device is connectedto the shank fastening device; and the second closing unit fasteningdevice is connected to the first connector of the spring housing.
 6. Thethread rolling head according to claim 4, wherein: the profile rollercage has a front plate and an intermediate plate; and the at least twoprofile rollers are held together with eccentric shafts rotatablybearing the at least two profile rollers between the front plate and theintermediate plate.
 7. The thread rolling head according to claim 6,wherein the profile roller cage has a plurality of distance boltsfastened to the front plate and extending between the front plate andthe intermediate plate.
 8. The thread rolling head according to claim 6,wherein: the module fastening device of the profile roller cagecomprises a central ring gear with external teeth arranged on theintermediate plate on a side facing away from the front plate; theprofile roller cage comprises a plurality of outer gears meshing withthe external teeth of the central ring gear, arranged also on theintermediate plate on the side facing away from the front plate; andeach of the plurality of outer gears is connected so as to be fixedagainst rotation to one of the eccentric shafts.
 9. The thread rollinghead according to claim 8, wherein the second connector of the springhousing comprises a coupling section engaging in a form-locking mannerin the central ring gear of the profile roller cage.
 10. The threadrolling head according to claim 9, wherein: the coupling section isformed as a splined shaft; the central ring gear on an inner surfacethereof has a plurality of engaging grooves running in an axialdirection of the thread rolling head; and and the splined shaft engagesinto the plurality of engaging grooves.
 11. The thread rolling headaccording to claim 10, wherein a division of the splined shaft and adivision of the plurality of engaging grooves are non-uniform such thatthe coupling section can engage in the central ring gear in preciselyone position of rotation.
 12. The thread rolling head according to claim5, wherein: the first connector of the spring housing has a couplingsection; the second closing unit fastening device comprises a couplingsection in form-locking engagement with the coupling section of thespring housing.
 13. The thread rolling head according to claim 5,wherein: the first closing unit fastening device has a coupling section;and the fastener of the shank comprises a coupling section inform-locking engagement with the coupling section.
 14. The threadrolling head according to claim 4, wherein the profile roller cage andthe spring housing are rotatable relative to each other withpre-tensioning or relaxing of the spring mounted in the spring housingand with changing of spacing of the profile rollers.
 15. The threadrolling head according to claim 14, wherein: the spring housing has anannular groove running in a peripheral direction about an outer surface;and an actuating clip with a catch is fastened within the annular groovesuch that rotation of the spring housing relative to the profile rollercage is possible using the actuating clip.
 16. The thread rolling headaccording to claim 15, wherein the actuating clip has an actuatingsection to which the catch is releasably fastened.